The invention relates to a method and arrangement for computer assisted upshifting in motor vehicles.
When motor vehicle gearboxes shift to higher gears which have lower gear ratios, the engine speed drops. In semi-automatic and fully automatic gear change systems, preferably for mechanical stepped gearboxes, the engine speed is then adjusted by adjustment of the fuel quantity injected, and if the engine speed would drop at the time of upshift an exhaust brake may also be activated momentarily during the gear change so that the engine speed drops more quickly to a speed which is synchronous with the speed of the next gear.
U.S. Pat. No. 4787044 describes a solution whereby the exhaust brake is activated during the course of upshift so that the engine speed comes down more quickly to a speed synchronous with the next gear. However, that solution uses an automated clutch function which disengages the engine from the gearbox, after which fuel adjustment and exhaust brake activation take place at the time of upshift in order to come down quickly to synchronous speed. Since the clutch disengages, the achievement of synchronous speed is not so critical, since the clutch can accommodate remaining speed differences during its re-engagement, by frictional absorption. This means that each upshift can take place with exhaust brake activation resulting in an approximately synchronous speed, and any remaining speed differences after exhaust brake adjustment are adjusted by the fuel and/or are absorbed in the clutch when it re-engages.